1. Fields of the Invention
The present invention relates to a method for control of electrochromic devices, especially to a method for control of electrochromic devices by which the response time for coloration and the transmittance of the electrochromic devices are maintained within a preset range without being affected by ambient temperature, setting time and aging of the materials used. Thus the electrochromic device is more convenient to use and having more practical value.
2. Descriptions of Related Art
Along with fast development of technology, various kinds of special materials have been invented. Electrochromic devices are devices that have the possibility to change their color reversibly by applying an external voltage. The coloration and bleaching of the electrochromic device are initiated by a drive voltage. After being driven by the voltage, the electrochromic device is changed from transparent state to colored state. The electrochromic device is a multi-layer electrochemical appliance that has the property of color changing due to electrochemical redox reactions after being applied with a voltage. Thus the electrochromic devices can be applied to change optical transmittance of the glass for blocking intense sunlight or for providing privacy.
While in use, the transmittance is reduced, the absorbance is increased and the color is getting deeper when a positive voltage is applied to the electrochromic device. Once a negative voltage is applied to the electrochromic device, the transmittance is increased, the absorbance is decreased and the color is getting lighter. By applying positive and negative voltage alternately, the electrochromic device carries out oxidation or reduction reaction for adjustment of transmittance.
However, although the transmittance of the electrochromic device can be adjusted to a desired value by switching between the positive and negative voltages applied, the response time for coloration and the transmittance are still affected by other factors including ambient temperature, setting time and aging of the material used. These all cause inconvenience in operation of the electrochromic device and there is room for improvement.
Thus there is a need to provide a method for control of electrochromic devices having more practical value.